Color is attractive and interesting to everyone. Consequently, control of color is important to all producers, buyers, sellers, and users of colored materials. In various ways, color is an indication of freshness, quality, or other desirable (or undesirable) characteristics of goods. To assure acceptability, saleability, and favorable price - especially in contracts and monitoring of conformance to specifications - numerical expression of color is greatly superior to verbal descriptions. Disagreements concerning words or visual comparisons with samples are all too likely and frequent. Such disagreements underlie much unÂ- pleasantness and loss in commerce in consumer goods. Such loss of money and good will must amount to billions of dollars per year, world wide. Persistent efforts to substitute measurements of color for visual judgment have marked the twentieth century. Because visual perception of small color differences is so acute, the requirements for accuracy and world-wide reproÂ- ducibility of color measurements have been severe. Only during the last half century have practical spectrophotometers with adequate accuracy been availÂ- able.
